HYPERTENSION IN PAEDIATRICS

Priya Gajjar

Paediatric Nephrology

RED CROSS CHILDREN’S HOSPITAL

Case Study1yr 10mo girl

� Presented to local Level 2 Hospital

� 1st episode generalized tonic-clonic

seizures

� Concerns about her vision

Clinical Findings

� Depressed level of

consciousness

� No focal signs

� No meningism

� Pale

� Normal glucose

� Tachycardiac

� All pulses palpable

� Congestive cardiac failure..

� displaced apex

� enlarged liver

� gallop

� Anthropometry :

� Wt = 10,7 kg (25th centile)

� Ht = 85 cm (50th centile)

� COH = 47 cm (25th centile)

� Perinatal / Birth history :

� HIV + mother (not on HAART - no perinatal program)

� NVD at term, BW > 3 kg, good Apgars

� Well neonate, no interventions

� HIV PCR negative at 3 months of age

� Immunizations :� UTD

� BCG at birth

� Growth

� Growing along the 50th centile and fell to the 25th centile two months ago

� No history of toxin ingestion

� Significant Previous Medical history

� TB treatment at local clinic 2 months prior

� Coughing > 1 month

� LOW (wt ↓50th to 10th centile)

� Household TB contact

� Reactive Tine

Investigations

� Normal electrolytes

� Glucose

� Calcium

� Urea and Creatinine

� Normal CSF

� FBC :

� WCC 10.6 Hb 8.6 MCV 64.8 Plt 807

� CRP : 12.3

� ESR : 35

� CT brain

� Cortical Atrophy

� And finally a BP was done….she was found

to be HYPERTENSIVE IN ALL 4 LIMBS

� Initial values of 190-200/130-140

Working diagnosis …

� HYPERTENSIVE ENCEPHALOPATHY with seizures and depressed level of consciousness

� CONGESTIVE CARDIAC FAILURE secondary to LONGSTANDING HYPERTENSION

� Possible RENO-VASCULAR cause for her hypertension

Further investigations prior to referral

� Ultrasound Abdomen :

� Rt kidney 6.5 cm and Lt kidney 8.5 cm.

� Ureters and bladder normal.

� Nil other intra –abdominal abnormalities found

� CT Abdomen :

� Rt kidney smaller than Lt

� Rt renal artery diameter (3.4 mm) is smaller than Lt (3.8 mm).

� No aneurysms

� Aorta normal in size.

� Stabilised

� Antihypertensives commenced

� Transferred to RXH

� Clinically significantly improved

Investigations at RXH

� Doppler Ultrasound

KUB

� Rt kidney 60mm,

Lt kidney 82mm

� Rt renal artery stenosis

� Tardus parvus doppler

waveform with decreased

peak systolic velocity

Mag 3

Essentially a solitary

kidney

Rt kidney functioning at

10%

Lt kidney 90%

� Echocardiogram

� Dilated cardiomyopathy

� Ejection Fraction 26%

�▲Rt Renal Artery Stenosis

� ▲▲? Takayasu’s Arteritis

� Very young presentation

� ? In the setting of possible active TB

� Very focal disease

� ▲▲Congenital

� Fibromuscular dysplasia

Treatment

� ? To treat with anti-inflammatories� ESR ranged from 19 to 46

� Already on TB therapy� Needed an angiogram; concerns re acutely inflamed vessels

� Pulsed with Medrol

� One dose IVI Cyclophosphamide

� Methotrexate and Prednisone

� Antihypertensives� Amlodipine

� Lasix

� Spironolactone

� Atenolol

� Angiogram

� Severe Rt renal artery stenosis, tapering to 1mm

� Normal Aortic arch and head and neck vessels

� Normal Abdominal Aorta, SMA and iliacs

� Mx

� Underwent a laparoscopic Rt Nephrectomy

� Good post-op recovery

� Progress

� Weaned off all her antihypertensives

� Kept on small dose Enalapril for the cardiomyopathy

Paediatric Hypertension

� Considereable advances have been made in the

detection, evaluation and management of

hypertension, as well as in obesity-related

hypertension in children and adolescents.

� Publication of national norms

� BP measurement in the routine paediatric examination

� Identify and treat secondary forms of hypertension

� Detection of mild elevations in BP representing early onset of

essential hypertension

� Rising prevalence of Hypertension in the paediatric population is related to the epidemic of childhood obesity

� 25% of children in US are overweight

� 11% are obese

� Childhood obesity contributes to the development of adult obesity, with its subsequent cardiovascular events

� 70% of obese adolescents become obese adults

� The Fourth Report on the Diagnosis,

Evaluation, and Treatment of High Blood

Pressure in Children and Adolescents

� Pediatrics, 2004;114;555-576

Normograms

� The revised BP tables include the 50th, 90th,

95th and 99th percentiles for gender, age and

height

� 1999-2000 National Health and Nutrition

Examination Survey

DEFINITIONS

� Adults: BP > 140/90 → 120/80mmHg

� Systolic Blood Pressure and/or a diastolic BP that is on repeated measurements >/=95th%

� Prehypertension replaces High normal BP

� Syst or diast BP between 90th - 95th centiles

� Indication for lifestyle modification and continued monitoring

� Adults and adolescents with BP > 120/80 should be considered prehypertensive

� Affects clinical management with additional resources required at all levels of health care

� Systolic BP > 100 + (3 x pat’s age in yrs)

� Diastolic BP > 70 + (1,5 x pat’s age in yrs)

Staging of Blood Pressure

� Management plan for evaluation and treatment

� Difference between 95th and 99th percentile BP is 7 to 10mmHg.

� Stage 1 Hypertension

� Syst or diast BP between 95th – to 5mmHg above the 99th centile

� Evaluate before initiating treatment, unless symptomatic

� Stage 2 Hypertension

� Syst or diast BP >5mmHg above the 99th centile

� Prompt evaluation and treatment

� Symptomatic require immediate consultation with experts

Measurement of Blood Pressure

� Appropriate cuff

� Bladder width at least 40% of the arm circumference at a point midway between the olecranon and the acromion

� Bladder length should cover 80 to 100 % of the circumference of the arm

� Manometers

� BP tables are based on auscultatory measurements

� Aneroid

� Oscillometric devices

� Measures mean BP, then calculates the syst and diast BP

24-hour Ambulatory BP

� BP Load

� Percentage of measurements above the 95th percentile

� Over 50%, closely related to end organ damage

� Physiological fall in nocturnal BP and rise with wakening

� Non-dipping status and nocturnal hypertension is described in children with secondary hypertension as opposed to patients with essential hypertension

� White-coat hypertension:

� BP>95th %, when measured in clinic, whereas the patient’s average BP is <90th % outside of a clinical setting.

Essential Hypertension

� Usually mild or stage 1 hypertension

� Positive family history of hypertension or of cardiovascular disease.

� Familial component with genetic factors contributing 40-50%

� Likely to be related to multiple genes

� Frequently overweight

� Prevalence of hypertension increases progressively with increase in BMI

� Hypertension is detectable in 30% of overweight children

� Clustering of other cardiovascular risk factors

� Hyperlipidaemia, truncal obesity, insulin resistance

� Children with Essential Hypertension had

lower birth weights

� BW <2.5kg, 38% were hypertensive

� Elevated Uric acid levels

� Inhibit proliferation of glomerular endothelial cells

� Rx Allopurinol?

� Predictor of cardiovascular risks in adults

Causes of Secondary Hypertension

Renal Parenchymal Dysplasia, chronic GN,

Reflux Nephropathy,

Wilm’s

Reno-vascular Takayasu’s Arteritis

Cardiac Co-arctation of Aorta

Endocrine Phaeochromocytoma,

Cushings, Conn’s

Central Tumours, Benign raised

intracranial hypertension

Renovascular Hypertension

� Potentially amenable to curative treatment

� Accounts for 5-10% of all childhood hypertension.

� Angiography still the gold standard imaging

modality

� In general ACEI are contraindicated in patients

suspected of having renovascular hypertension

Causes of Renovascular Hypertension

� Fibromuscular Dysplasia

� Syndromic

� Neurofibromatosis type 1

� Tuberous Sclerosis

� William’s Syndrome

� Vasculitic

� Takayasu’s

� Polyarteritis Nodosa

� Extrinsic Compression

� Neuroblastoma

� Wilm’s

� Others

� Umbilical vein catheterisation

Causes of Sustained Hypertension (PD Thomson)

Chronic Glomerulonephritis 30%

Chronic Pyelonephritis 20%

Coarctation of Aorta 10%

Cystic Disease of Kidney 10%

Haemolytic Uraemic Syndrome(HUS) 8%

Renovascular 8%

Hypoplastic/Dysplastic Kidneys 4%

Essential 4%

Others – phaeo, pap nec, Wilms 6%

History in paediatric hypertension -1

Family history hpt, pre-

eclampsia, renal dx,

tumours

Essential hpt, inherited

dx, familial

phaeochromocytoma

Neonatal hx Birth weight, Use of

umbilical catheters

Dietary hx Sodium & calorie intake

Headaches, dizziness,

epistaxis

Non-specific symptoms

History in paediatric hypertension-2

Abdominal pain, dysuria,

frequency, nocturia, enuresis

Underlying renal disease

Joint pains/swelling, rash

facial/peripheral oedema,

Collagen vascular disease

or other nephritis

Wt loss, FTT, excessive

sweating, flushing, pallor, fever

Phaeochromocytoma

Muscle cramps, weakness,

constipation

Hyperaldosteronism with

hypokalaemia

Drug History Steroids, NSAIDs, Ritalin

DRUGS CAUSING HYPERTENSION

� Adrenaline

� Amphetamines

� Caffeine

� Carbamazepine

� Cocaine

� Cyclosporin

� Erythropoietin

� Ketoconazole

� Methylphenidate (Ritalin)

� Metoclopramide

� NSAID’s

� OCP’s

� Promethazine

� Steroids

� Terbutaline

Clinical Assessment

� General

� Dysmorphism, vitals, wt & ht, BMI

� Skin, joints

� Renal

� Endocrine

� Cardiac

� Central

Diagnostic - Step 1

� Renal

� Urine dipstix, MC&S, Protein: creatinine ratio

� U&E, Creatinine, Ca, and Po4

� Ultrasound of kidneys

� Sizes

� Dopplers of renal vessels

� Cardiac

� CXR, ECG,

� Echo, to exclude Coarctation

� Inflammation

� Mantoux

� FBC & ESR

Diagnostic – step 2(depending on findings in step 1)

� RENAL:

� Glomerulonephritis

� ASOT, Anti-DNAse B,

� C3/C4

� ANF, ANCA’s (if nephritis/vasculitis suspected)

� Reflux Nephropathy

� DMSA scan

� MCUG (if unexplained renal scarring) Plasma Renin

� Renovascular Disease

� Plasma Aldosterone and renin

� Mag 3 / Captopril renogram

� CT scan / MRA

� Angiography with renal vein renin sampling

Diagnostic – step 2(depending on findings in step 1)

� ENDOCRINE:

� Phaeochromocytoma

� Urinary Catecholamine metabolites (VMA/NMA – either as spot or 24hr collections)

� Adrenal/abdominal U/S

� MIBG scan

� CT/MRI

� Others

� Cortisol (early morning)

� 24hr Urine Steroid profile

� Renin

� U/S / CT of adrenals

Diagnostic – step 2(depending on findings in step 1)

� CENTRAL:

� CT Scan head

End Organ Damage

Cardiac CXR

ECG

Echo

Eyes Ophthalmology review

Renal Urine dipstix

Urea & Creatinine

•Echocardiography is recommended as a primary tool for evaluating patients for

target-organ abnormalities by assessing the presence or absence of LVH.

•If end-organ damage is discovered, hypertension should be aggressively

managed.

Evaluation of Co-morbidities

� Fasting lipid panel

� Fasting glucose; HbA1C

Newer Imaging Techniques

� CT Angiogram� Disease of aorta

� MRI/Angiogram� Aorta and main renal arteries

� Conventional Angiogram� Most accurate

� General anaesthetic

CT Angiogram MRI angio

Mx of Acute Hypertension

� Hypertensive Crisis

� Medical emergency with end organ decompensation

� ICU or High Care Setting

� Frequent BP monitoring and Neuro observations

� Reduce BP slowly

� 1/3 of total desired reduction in 1st 12 hrs

� Next 1/3 over 12-36hrs

� Last 1/3 over 36-72hrs

� Rx

� IVI Sodium Nitroprusside 0.5 – 8ug/kg/min

� IVI Labetalol 0.25 – 4mg/kg/hour

� Caution in heart failure and Asthma

� IVI Frusemide 1-5mg/kg/dose slowly

� If fluid overloaded

Mx of Acute Hypertension

� Severe Hypertension

� ~ 20mmHg above the 95th percentile

� Rx oral agents

� Amlodipine newer agent

� 0.2mg/kg/dose po every 6-12hours

� Nifedipine 0.15-0.3mg/kg /dose 4-6hrly Nourse SAJCH 2007

� Oral Hydralazine 0.4-1mg/kg/dose(or ivi)

� Lasix 1-4mg/kg/day (if fluid overloaded)

� The shorter the duration of being hypertensive, the quicker the BP can be brought down

Chronic Hypertension

� A – ACEI� Captopril

� Enalapril/Ramipril/Perindopril

� B – B Blocker� Propanolol

� Atenolol/Metoprolol

� Labetalol – Combination Alpha and B Blocker

� C – Calcium Channel Blocker� Nifedipine

� Amlodipine

Chronic Hypertension

� D – Diuretic� Lasix

� Spironolactone

� E – Everything else

� Alpha blocker

� Prazosin/Doxazosin

� Direct arteriolar dilatation

� Hydralazine, Minoxidil

� Central acting agents

� Clonidine, Methyldopa

Therapeutic Lifestyle Changes

� Weight reduction

� Regular physical activity and restriction of

sedentary activity

� Family-based intervention improves success

Angioplasty

� Balloon dilatation

� Stents

Percutaneous Transluminal Angioplasty(PTA)

PTA for control of

Hypertension

(12 patients)

14 cases

Aortic dilatations 4/4 successful

Renal Vessel dilatation 6/10 successful

Surgical

� Nephrectomy

� Auto-transplant

� Re-vascularisation

� Graft bypass

Take Home Message

� Hypertension is increasing in prevalence in

children, likely related to the epidemic of

childhood obesity

� Proper BP measurement is critical in establishing

the diagnosis of hypertension.

� Secondary causes of hypertension are more

common in children than in adults and require

more extensive work-up.

� Overweight children are more likely to have essential hypertension so evaluation can be limited in these patients.

� Childhood hypertension tracks into adulthood. The impact of hypertension on the risk of cardiovascular disease has been well established, thus the general paediatrician must be comfortable at evaluating and treating elevated blood pressures

� Co-morbidities, if present should be promptly treated.

� If end-organ damage is discovered, hypertension should be aggressively managed.